Centerless grinding machine



June 27, 1950 A. SCRIVENER CENTERLESS GRINDING MACHINE Filed Jan. 2,1948 EMU. WHWH uuhw ARTHUR SCRIVENER BY WATTO EYS Patented June 27, 1950Application January 2, 1948, Serial No. 194 In Great Britain September28, 1946 2 Claims.

This invention has reference to improvements in or connected withcentreless grinding machines, more particularly that type of machine inwhich the grinding wheel is associated with the control wheel for thepositioning of the workpiece, and the object of the present invention isto avoid damage to the ends of the workpiece caused by skidding orslipping of the workpiece in relation to the grinding wheel during thefeeding-in or feeding-out traverse of the workpiece so as to ensure anaccurate co-ordination between the control wheel, grinding wheel and theworkpiece.

The invention consists of the provision in centreless grinding machinesof lead-in and/or leadout rolls for the control of the workpiecerelative to the grinding wheel, said rolls being freely mounted incontiguity with the periphery of the grinding wheel and locatedsubstantially within the width of the control wheel for the purpose setforth.

One means of carrying the present invention into practice as applied tothe feeding or traversing of a workpiece through the gap normallyobtaining between the periphery of the grinding wheel and the peripheryof the control wheel is illustrated by the accompanying drawings, inwhich Fig. 1 is an end elevation of part of a centreless grindingmachine showing the embodiment therein of the subject-matter of thepresent invention.

Fig. 2 is a front elevation of the mechanism seen in Fig. 1 looking onthe control wheel.

Fig. 3 is a detail view showing a modification in the form of the idleroller.

Referring first more particularly to Figs. 1 and 2 of the drawings,there is located on either side of the grinding wheel a a. small idleroller 1) the axes whereof are in alignment, and the effective part ofthe peripheries whereof are located in substantial alignment with theactive face-line of the grinding wheel disposed between the pair of idlerollers 12. 1

Desirably the idle rollers are spring-urged in the direction of thecontrol wheel and this is effected by freely mounting each of the idlerollers at the lower end of dependent arms 11 clamped to a spindle e.Secured to the spindle e is a laterally extending arm 7 whichco-operates with a set-screw g adjustably mounted in the frame h of themachine, the set-screw serving to limit the motion of the arm d when theworkpiece a is withdrawn.

The arm d is flexibly anchored to the frame of the machine by means of acoiled tension 2 spring which is adjustably connected by means of an eyebolt Z the shank whereof passes through a boss in the frame h of themachine.

The control wheel c is preferably arranged so that the width issubstantially equal to the width of the two idle rollers b plus thewidth of the grinding wheel a. By this means when the workpiece isintroduced between the control wheel and the grinding wheel the lead-inend of the workpiece is seized between the spring-urged lead-in rollerand the periphery of the control wheel and is fed thereby to thegrinding wheel without damage to the lead-in edge of the workpiece;likewise at the termination of the grinding operation the trailing endof the workpiece is led out between the other spring-urged roller andthe control wheel so as to prevent damage to the trailing end of theworkpiece upon the completion of the grinding operation.

Referring now more particularly to Fig. .3 of the drawings whichillustrates a modification in the form of the idle roller bwhere it maybe desired to govern the feed of a workpiece upon which it is requiredto produce a screw-thread by grinding, each idle roller would be formedwith an annular tooth b the tooth having a configuration conforming tothat of the tooth to be ground on the workpiece by means of the grindingwheel so that by longitudinally adjusting the setting of thespring-urged rollers relative to the grinding wheel a the pitch of theteeth can be co-ordinated with the pitch of the teeth of the grindingwheel to ensure accurate positioning and co-ordination of the workpieceto the grinding wheel during the rotational traverse of the Workpieceacross the face of the grinding wheel in adjacency to the control wheel.

In Fig. 3 of the drawings it will be observed that the idle roller 2)which carries the tooth b is mounted on the spindle d laterallyextending from the free end of the arm d by means of a collar d and aheaded set screw 01 located within a recess in the idle roller 12, anyrequired adjustment of the spindle d being effected by means of the twonuts (1 mounted on either side of the arm d.

Iclaim:

1. In a centreless thread grinding machine having a thread grindingwheel and a control wheel mounted upon parallel spaced axes, the controlwheel being movable transversely toward and away from the grinding wheeland having a surface extending axially beyond both sides of the grindingwheel, a pair of coaxial work support rollers, a raised, annular,circumferencontrol wheel, a mounting spindle on the end of each of saidarms and roller bearings axially adjustably mounted on each of saidspindles. A. S CRIVF;lmillit.

REFERENCES CITED The following references are of record in the file ofthis Ipatent:

Number 10 Number UNITED STATES PATENTS Name Date Hoeg May 24 1932FOREIGN PATENTS Country Date Great Britain May 23, 1929 Great BritainJuly 18, 1929

